Liquid crystal display apparatus

ABSTRACT

According to one embodiment, a liquid crystal display apparatus includes a first substrate, a second substrate and a liquid crystal layer. The first substrate includes a gate wiring, a source wiring, an insulating film, a shield electrode, a primary pixel electrode, a peripheral wiring and a peripheral connecting electrode. The shield electrode is opposite to at least a portion of the gate wiring and the source wiring. The peripheral connecting electrode electrically connects the shield electrode and the peripheral wiring. The second substrate includes a pair of primary common electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2011-174114, filed Aug. 9, 2011, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a liquid crystaldisplay apparatus.

BACKGROUND

Currently, the development of planar display apparatuses is beingactively pursued and, of the various technologies applicable, liquidcrystal displays are attracting great attention because of theiradvantages of being light, thin, and energy-efficient. Particularly inactive matrix liquid crystal displays, in which a switching element isintegrated in each pixel, attention is focusing on a structure in whicha transverse electric field (including a fringe electric field) such asan in-plane switching (IPS) mode or a fringe field switching (FFS) modeis used. A liquid crystal display with such a transverse electric fieldmode includes a pixel electrode and a counterelectrode formed on anarray substrate and switches liquid crystal molecules by a transverseelectric field substantially parallel to the principal plane of thearray substrate.

In contrast, there is also proposed a technology that switches liquidcrystal molecules by producing a transverse or an oblique electric fieldbetween a pixel electrode formed on an array substrate and a commonelectrode formed on a countersubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing a configuration of a liquidcrystal display apparatus according to an embodiment and an equivalentcircuit thereof;

FIG. 2 is a plan view schematically showing a structure example of apixel of an array substrate shown in FIG. 1;

FIG. 3 is a sectional view schematically showing a structure example ofthe array substrate along line in FIG. 2;

FIG. 4 is a sectional view schematically showing a structure when aliquid crystal display panel shown in FIG. 2 is cut along line IV-IV;

FIG. 5 is a diagram illustrating an electric field produced between apixel electrode and a common electrode in the liquid crystal displaypanel shown in FIGS. 2 and 4 and a relationship between a director andtransmittance of liquid crystal molecules by the electric field;

FIG. 6 is a plan view schematically showing a corner of a display areaand a non-display area of the array substrate;

FIG. 7 is a sectional view schematically showing a structure example ofthe array substrate along line VII-VII in FIG. 6; and

FIG. 8 is a plan view schematically showing entire peripheral connectingelectrodes and peripheral wirings in the array substrate.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided a liquidcrystal display apparatus comprising: a first substrate, a secondsubstrate, and a liquid crystal layer. The first substrate includes agate wiring located in a display area and configured to extend in afirst direction, a source wiring located in a display area andconfigured to extend in a second direction orthogonal to the firstdirection, an insulating film provided on the gate wiring and the sourcewiring, a shield electrode provided on the insulating film and oppositeto at least a portion of the gate wiring and the source wiring, aprimary pixel electrode located in the display area, provided on theinsulating film, positioned with an interval from the shield electrode,and configured to extend in the second direction, a peripheral wiringlocated in a non-display area outside the display area, and a peripheralconnecting electrode electrically connecting the shield electrode andthe peripheral wiring. The second substrate includes a pair of primarycommon electrodes located in the display area, positioned across theprimary pixel electrode in the first direction and configured to extendin the second direction. The liquid crystal layer is held between thefirst substrate and the second substrate.

According to another embodiment, there is provided a liquid crystaldisplay apparatus comprising: a first substrate, a second substrate, anda liquid crystal layer. The first substrate includes a gate wiringconfigured to extend in a first direction, a source wiring configured toextend in a second direction orthogonal to the first direction, aninsulating film provided on the gate wiring and the source wiring, ashield electrode provided on the insulating film and opposite to atleast a portion of the gate wiring and the source wiring, a primarypixel electrode provided on the insulating film, positioned with aninterval from the shield electrode, and configured to extend in thesecond direction, a peripheral wiring provided in the same layer as thesource wiring, and a peripheral connecting electrode electricallyconnecting the shield electrode and the peripheral wiring. The secondsubstrate includes a pair of primary common electrodes positioned acrossthe primary pixel electrode in the first direction and configured toextend in the second direction. The liquid crystal layer is held betweenthe first substrate and the second substrate.

According to another embodiment, there is provided a liquid crystaldisplay apparatus comprising: a first substrate, a second substrate, anda liquid crystal layer. The first substrate includes a gate wiringlocated in a display area and configured to extend in a first direction,a first interlayer film provided on the gate wiring, a source wiringconfigured to extend in a second direction orthogonal to the firstdirection on the first interlayer film in the display area, a secondinterlayer film provided on the source wiring, a primary pixel electrodeconfigured to extend in the second direction on the second interlayerfilm in the display area, a secondary pixel electrode connected to theprimary pixel electrode and configured to extend in the first direction;and a peripheral wiring provided in a Π shape on the first interlayerfilm in a non-display area outside the display area. The secondsubstrate includes a primary common electrode located in the displayarea, arranged parallel to the primary pixel electrode, and configuredto extend in the second direction. The liquid crystal layer is heldbetween the first substrate and the second substrate and includes a cellgap narrower than an interval between the primary pixel electrode andthe primary common electrode.

A liquid crystal display apparatus according to an embodiment will bedescribed in detail below with reference to the drawings. FIG. 1 is adiagram schematically showing a configuration of a liquid crystaldisplay apparatus according to an embodiment and an equivalent circuitthereof.

As shown in FIG. 1, the liquid crystal display apparatus includes anactive matrix type liquid crystal display panel LPN. The liquid crystaldisplay panel LPN includes an array substrate AR as a first substrate, acountersubstrate CT as a second substrate arranged opposite to the arraysubstrate AR, and a liquid crystal layer LQ held between the arraysubstrate AR and the countersubstrate CT. The liquid crystal displaypanel LPN described above includes a display area ACT where images aredisplayed. In the display area ACT, m×n pixels PX arranged in a matrixshape are provided (m and n are positive integers).

The liquid crystal display panel LPN includes n gate wirings G (G1 toGn), n auxiliary capacitance wirings C (C1 to Cn), and m source wiringsS (S1 to Sm) and the like in the display area ACT. The gate wiring G andthe auxiliary capacitance wiring C extend substantially linearly, forexample, in a first direction X. The gate wirings G and the auxiliarycapacitance wirings C are alternately arranged parallel to each other ina second direction Y crossing the first direction X. Here, the firstdirection X and the second direction Y are substantially orthogonal toeach other. The source wiring S crosses the gate wiring G and theauxiliary capacitance wiring C. The source wiring S extendssubstantially linearly in the second direction Y. Incidentally, the gatewirings G, the auxiliary capacitance wirings C, and the source wiring Sdo not necessarily extend linearly and a portion thereof may be curved.

One end of each of the gate wirings G is pulled out of the display areaACT to be connected to a gate driver GD. One end of each of the sourcewirings S is pulled out of the display area ACT to be connected to asource driver SD. At least a portion of each of the gate driver GD andthe source driver SD is connected to, for example, a drive IC chip 2.The drive IC chip 2 is formed on the array substrate AR and contains,for example, a controller.

Each of the pixels PX includes a switching element SW, a pixel electrodePE, and a common electrode CE and the like. The auxiliary capacitancewiring C is electrically connected to a voltage application unit VCS towhich an auxiliary capacitance voltage is applied.

In the present embodiment, the liquid crystal display panel LPN isconfigured in such a way that while the pixel electrode PE is formed onthe array substrate AR, at least a portion of the common electrodes CEis formed on the countersubstrate CT and an electric field producedbetween the pixel electrode PE and the common electrode CE is mainlyused to switch liquid crystal molecules of the liquid crystal layer LQ.The electric field produced between the pixel electrode PE and thecommon electrode CE is an oblique electric field slightly inclined withrespect to an X-Y plane defined by the first direction X and the seconddirection Y or the principal plane of the substrate (or a transverseelectric field approximately parallel to the principal plane of thesubstrate).

The switching element SW is constituted of, for example, an n-channelthin-film transistor (TFT). The switching element SW is electricallyconnected to the gate wiring G and the source wiring S. The switchingelement SW may be of top gate type or bottom gate type. The switchingelement SW has a semiconductor layer formed of, for example,polysilicon, and the semiconductor layer may also be formed of amorphoussilicon.

The pixel electrode PE is arranged in each pixel PX and is electricallyconnected to the switching element SW and an auxiliary capacitanceelement CS. The common electrode CE is arranged commonly to the pixelelectrodes PE of a plurality of pixels PX via the liquid crystal layerLQ. The pixel electrode PE and the common electrode CE as describedabove are formed of a conductive material having light transmissionproperties such as indium tin oxide (ITO) and indium zinc oxide (IZO),but may also be formed of other metallic materials such as aluminum.

FIG. 2 is a plan view schematically showing a structure example of onepixel PX of the array substrate AR shown in FIG. 1. Here, a plan view onthe X-Y plane is shown.

As shown in FIG. 2, the pixel PX has, as indicated by a two-dot chainline, a rectangular shape in which the dimension in the first directionX is less than that in the second direction Y. The gate wiring G extendsin the first direction X. The auxiliary capacitance wiring C is arrangedbetween the adjacent gate wirings G and extends in the first directionX. The auxiliary capacitance wiring C is arranged in a substantiallycentral portion of the pixel. The source wiring S extends in the seconddirection Y. The pixel electrode PE is arranged between the adjacentsource wirings S. The pixel electrode PE is positioned between the gatewirings G.

The switching element SW is electrically connected to the gate wiring Gand the source wiring S. The switching element SW is provided at thepoint of intersection of the gate wiring G and the source wiring S. Asemiconductor layer 13 of the switching element SW is provided in aregion overlapping with the source wiring S by hardly protruding out ofthe source wiring S and restricts the reduction of area of an openingcontributing to the display.

FIG. 3 is a sectional view schematically showing a structure example ofthe array substrate AR along line III-III in FIG. 2.

As shown in FIGS. 2 and 3, an auxiliary capacitance electrode 14 isprovided on a first insulating substrate 10. The auxiliary capacitanceelectrode 14 is formed integrally with the semiconductor layer 13 usingthe same material. A gate insulating film 16 is provided on the firstinsulating substrate 10 and the auxiliary capacitance electrode 14, andthe auxiliary capacitance wiring C and others are provided on the gateinsulating film 16. The auxiliary capacitance electrode 14 and theauxiliary capacitance wiring C overlapping with each other form theauxiliary capacitance element CS. The auxiliary capacitance electrode 14hardly protruding out of the auxiliary capacitance wiring C andrestricts the reduction of area of an opening contributing to thedisplay.

A first interlayer insulating 11 is provided on the gate insulating film16 on which the auxiliary capacitance wiring C and others are formed. Aconnecting electrode 15 and the source wiring S are provided on thefirst interlayer insulating 11. The connecting electrode 15 and thesource wiring S are formed of the same material such as aluminum (Al) atthe same time. The connecting electrode 15 is connected to the auxiliarycapacitance electrode 14 through a contact hole CH1 formed in the gateinsulating film 16 and the first interlayer insulating 11. The sourcewiring S is connected to a source region of the semiconductor layer 13through a contact hole CH2 formed in the gate insulating film 16 and thefirst interlayer insulating 11.

A second interlayer insulating 12 is provided on the first interlayerinsulating 11, the connecting electrode 15, and the source wiring S. Ashield electrode SE and the pixel electrode PE are formed on the secondinterlayer insulating 12.

As shown in FIG. 2, the shield electrode SE is opposed to the gatewiring G and the source wiring S and is formed in a lattice shape. Thewidth of the shield electrode SE at a point opposite to the gate wiringG is greater than or equal to that of the gate wiring G, and the widthof the shield electrode SE at a point opposite to the source wiring S isgreater than or equal to that of the source wiring S.

The pixel electrode PE is positioned with an interval from the shieldelectrode SE and extends in the second direction Y. The pixel electrodePE includes a primary pixel electrode PA and a secondary pixel electrodePB electrically connected to each other.

The primary pixel electrode PA linearly extends in the second directionY from the secondary pixel electrode PB to the vicinity of theupper-side end and the lower-side end of the pixel PX. The primary pixelelectrode PA described above is formed in a band shape havingsubstantially uniform width in the first direction X.

The secondary pixel electrode PB is positioned in a region overlappingwith the auxiliary capacitance wiring C and is electrically connected tothe connecting electrode 15 through a contact hole CH3 formed in thesecond interlayer insulating 12. The secondary pixel electrode PB isformed to be wider than the primary pixel electrode PA. In the presentembodiment, the secondary pixel electrode PB is formed in an octagonalshape. The pixel electrode PE described above is arranged at asubstantially intermediate position of the adjacent source wirings S,that is, in the center of the pixel PX.

FIG. 4 is a sectional view schematically showing a structure when theliquid crystal display panel LPN shown in FIG. 2 is cut along lineIV-IV. Here, only portions needed for description are shown.

As shown in FIGS. 2 and 4, the common electrode CE includes a primarycommon electrode CA. The primary common electrode CA linearly extends inthe second direction Y substantially parallel to the primary pixelelectrode PA. A pair of the primary common electrodes CA adjacent toeach other is positioned across the primary pixel electrode PA in thefirst direction X. Alternatively, the primary common electrode CA isopposed to the respective source wiring S and extends substantiallyparallel to the primary pixel electrode PA. The primary common electrodeCA described above is formed in a band shape having substantiallyuniform width in the first direction X.

In the illustrated example, the pair of the primary common electrodes CAis arranged in the first direction X and is arranged at the left andright ends of the pixel PX. A plurality of the primary common electrodesCA is electrically connected to each other in the display area ACT or anon-display area R outside the display area ACT.

If the positional relationship between the pixel electrode PE and theprimary common electrode CA is focused on, it is clear that the pixelelectrode PE and the primary common electrode CA are arrangedalternately in the first direction X. The pixel electrode PE and theprimary common electrode CA are arranged substantially parallel to eachother. In this case, none of the primary common electrodes CA overlapsthe pixel electrode PE on the X-Y plane.

As shown in FIG. 4, a backlight unit 4 is arranged on the rear side ofthe array substrate AR constituting the liquid crystal display panelLPN. Various forms of units can be applied as the backlight unit 4 andunits using a light emitting diode (LED) or cold-cathode tube (CCFL) canbe applied and here, a description of a detailed structure thereof isomitted.

The array substrate AR is formed using the first insulating substrate 10having light transmission properties. The pixel electrode PE ispositioned on the inner side of the position of each line of theadjacent source wirings S.

A first alignment film AL1 is arranged on the surface of the arraysubstrate AR opposite to the countersubstrate CT and extends oversubstantially the entire display area ACT. The first alignment film AL1covers the pixel electrode PE and others and is arranged also on thesecond interlayer insulating 12. The first alignment film AL1 describedabove is formed of a material showing horizontal alignment.

The countersubstrate CT is formed using a second insulating substrate 20having light transmission properties. The countersubstrate CT includes ablack matrix BM, a color filter CF, an overcoat layer OC, the commonelectrode CE, a second alignment film AL2, or the like.

The black matrix BM demarcates each pixel PX and forms an opening APopposite to the pixel electrode PE. That is, the black matrix BM isarranged so as to be opposite to a wiring portion such as the sourcewiring S, gate wiring, auxiliary capacitance wiring, and switchingelement. Here, only a portion of the black matrix BM extending in thesecond direction Y is illustrated, but a portion extending in the firstdirection X may also be included. The black matrix BM is arranged on aninner surface 20A of the second insulating substrate 20 opposite to thearray substrate AR.

The color filter CF is arranged corresponding to each pixel PX. That is,the color filter CF is arranged in the opening AP on the inner surface20A of the second insulating substrate 20 and also a portion thereof isplaced onto the black matrix BM. The color filters CF arranged in thepixels PX adjacent in the first direction X have mutually differentcolors. For example, the color filters CF are formed of resin materialseach colored in one of the three primary colors, red, green, and blue. Ared color filter CFR made of a resin material colored red is arrangedcorresponding to a red pixel. A blue color filter CFB made of a resinmaterial colored blue is arranged corresponding to a blue pixel. A greencolor filter CFG made of a resin material colored green is arrangedcorresponding to a green pixel. The boundary of these color filters CFis in positions overlapping the black matrix BM.

The overcoat layer OC covers the color filter CF. The overcoat layer OCmitigates the influence of unevenness of the surface of the color filterCF.

The common electrode CE is provided on the side opposite to the arraysubstrate AR of the overcoat layer OC.

The second alignment film AL2 is arranged on the surface opposite to thearray substrate AR of the countersubstrate CT and extends oversubstantially the entire display area ACT. The second alignment film AL2covers the common electrode CE, the overcoat layer OC and the like. Thesecond alignment film AL2 described above is formed of a materialshowing horizontal alignment.

As shown in FIGS. 2 and 4, the first alignment film AL1 and the secondalignment film AL2 are alignment-treated (such as rubbing and photoalignment treatment) for initial alignment of liquid crystal moleculesof the liquid crystal layer LQ. A first alignment treatment directionPD1 for initial alignment of liquid crystal molecules by the firstalignment film AL1 and a second alignment treatment direction PD2 forinitial alignment of liquid crystal molecules by the second alignmentfilm AL2 are mutually parallel and oriented in opposite directions or inthe same direction. For example, the first alignment treatment directionPD1 and the second alignment treatment direction PD2 are, as shown inFIG. 2, substantially parallel to the second direction Y and oriented inthe same direction.

The array substrate AR and the countersubstrate CT as described aboveare arranged in such a way that the first alignment film AL1 and thesecond alignment film AL2 are opposite to each other respectively. Inthis case, a predetermined cell gap, for example, a cell gap of 2 to 7μm is formed by, for example, a columnar spacer formed of a resinmaterial integrally with one substrate between the first alignment filmAL1 of the array substrate AR and the second alignment film AL2 of thecountersubstrate CT. The interval between the primary pixel electrode PAand the primary common electrode CA is wider than the cell gap. That is,the cell gap of the liquid crystal layer held between the arraysubstrate AR and the countersubstrate CT is narrower than the intervalbetween the primary pixel electrode PA and the primary common electrodeCA. The array substrate AR and the countersubstrate CT are sealedtogether by a sealant SB outside the display area ACT while thepredetermined cell gap is formed.

The liquid crystal layer LQ is formed in a space surrounded by the arraysubstrate AR (first alignment film AL1), the countersubstrate CT (secondalignment film AL2), and the sealant SB and is held between the arraysubstrate AR and the countersubstrate CT. The liquid crystal layer LQdescribed above is constituted of, for example, a liquid crystalmaterial whose dielectric anisotropy is positive (positive type).

A first optical element OD1 is sealed to the outside surface of thearray substrate AR, that is, an outside surface 10B of the firstinsulating substrate 10 constituting the array substrate AR by using anadhesive or the like. The first optical element OD1 is positioned on theside opposite to the backlight unit 4 of the liquid crystal displaypanel LPN and controls the polarization state of incident light incidenton the liquid crystal display panel LPN from the backlight unit 4. Thefirst optical element OD1 contains a first polarizer PL1 having a firstpolarization axis (or a first absorption axis) AX1.

A second optical element OD2 is sealed to the outside surface of thecountersubstrate CT, that is, an outside surface 20B of the secondinsulating substrate 20 constituting the countersubstrate CT using anadhesive or the like. The second optical element OD2 is positioned onthe display surface side of the liquid crystal display panel LPN andcontrols the polarization state of emitted light emitted from the liquidcrystal display panel LPN. The second optical element OD2 contains asecond polarizer PL2 having a second polarization axis (or a secondabsorption axis) AX2.

The first polarization axis AX1 of the first polarizer PL1 and thesecond polarization axis AX2 of the second polarizer PL2 are, forexample, in an orthogonal spatial relationship and thus, the firstpolarizer PL1 and the second polarizer PL2 are cross Nicol-arranged. Inthis case, one polarizer is arranged so that the polarization axisthereof is parallel or orthogonal to the initial alignment direction ofliquid crystal molecules, that is, the first alignment treatmentdirection PD1 or the second alignment treatment direction PD2. If theinitial alignment direction is parallel to the second direction Y, thepolarization axis of one polarizer is parallel to the second direction Yor the first direction X.

In the example shown in (a) of FIG. 2, the first polarizer PL1 isarranged so that the first polarization axis AX1 thereof is orthogonalto the initial alignment direction (second direction Y) of liquidcrystal molecules LM (that is, parallel to the first direction X), andthe second polarizer PL2 is arranged so that the second polarizationaxis AX2 thereof is parallel to the initial alignment direction of theliquid crystal molecules LM (that is, parallel to the second directionY).

In the example shown in (b) of FIG. 2, the second polarizer PL2 isarranged so that the second polarization axis AX2 thereof is orthogonalto the initial alignment direction (second direction Y) of the liquidcrystal molecules LM (that is, parallel to the first direction X), andthe first polarizer PL1 is arranged so that the first polarization axisAX1 thereof is parallel to the initial alignment direction of the liquidcrystal molecules LM (that is, parallel to the second direction Y).

Next, the operation of the liquid crystal display panel LPN configuredabove will be described with reference to FIGS. 2 and 4.

As shown in FIGS. 2 and 4, the liquid crystal molecules LM of the liquidcrystal layer LQ is aligned so that the major axis thereof is orientedtoward the first alignment treatment direction PD1 of the firstalignment film AL1 and the second alignment treatment direction PD2 ofthe second alignment film AL2 in a state in which no voltage is appliedto the liquid crystal layer LQ, that is, no electric field is producedbetween the pixel electrode PE and the common electrode CE (duringoff-states). Such off-states correspond to the initial alignment stateand the alignment direction of the liquid crystal molecules LM duringoff-states corresponds to the initial alignment direction.

To be more precise, the liquid crystal molecules LM are not necessarilyaligned parallel to the X-Y plane and are frequently pre-tilted. Thus,the initial alignment direction of the liquid crystal molecules LM is adirection obtained by an orthogonal projection of the major axis of theliquid crystal molecules LM during off-states onto the X-Y plane. Tosimplify the description below, it is assumed that the liquid crystalmolecules LM are aligned parallel to the X-Y plane and rotate in a planeparallel to the X-Y plane.

Here, both of the first alignment treatment direction PD1 and the secondalignment treatment direction PD2 are substantially parallel to thesecond direction Y. The major axis of the liquid crystal molecules LMduring off-states is initially aligned, as indicated by a dashed line inFIG. 2, substantially parallel to the second direction Y. That is, theinitial alignment direction of the liquid crystal molecules LM isparallel to the second direction Y (or at 0° with respect to the seconddirection Y).

If, like the illustrated example, the first alignment treatmentdirection PD1 and the second alignment treatment direction PD2 areparallel and oriented in the same direction, the liquid crystalmolecules LM are aligned substantially horizontally (the pre-tilt angleis substantially zero) near an intermediate portion of the liquidcrystal layer LQ in the cross section of the liquid crystal layer LQ,and with this point as a boundary, the liquid crystal molecules LM arealigned with a pre-tilt angle so as to be symmetric in the vicinity ofthe first alignment film AL1 and the vicinity of the second alignmentfilm AL2 (splay alignment).

As a result of aligning the first alignment film AL1 to the firstalignment treatment direction PD1, the liquid crystal molecules LM nearthe first alignment film AL1 are initially aligned to the firstalignment treatment direction PD1 and as a result of aligning the secondalignment film AL2 to the second alignment treatment direction PD2, theliquid crystal molecules LM near the second alignment film AL2 areinitially aligned to the second alignment treatment direction PD1. Ifthe first alignment treatment direction PD1 and the second alignmenttreatment direction PD2 are parallel to each other and oriented in thesame direction, as described above, the liquid crystal molecules LM arein a splay alignment and with the intermediate portion of the liquidcrystal layer LQ as a boundary, as described above, the alignment of theliquid crystal molecules LM near the first alignment film AL1 on thearray substrate AR and the alignment of the liquid crystal molecules LMnear the second alignment film AL2 on the countersubstrate CT aresymmetric with respect to a horizontal line. Thus, optical compensationis made also in a direction tilted from the normal direction of thesubstrate. Therefore, if the first alignment treatment direction PD1 andthe second alignment treatment direction PD2 are parallel to each otherand oriented in the same direction, light leakage in the black displayis small so that it becomes possible to realize a high contrast ratioand to improve display quality.

If the first alignment treatment direction PD1 and the second alignmenttreatment direction PD2 are parallel to each other and oriented inopposite directions, the liquid crystal molecules LM are aligned with asubstantially uniform pre-tilt angle near the first alignment film AL1,near the second alignment film AL2, and in the intermediate portion ofthe liquid crystal layer LQ in the cross section of the liquid crystallayer LQ (homogeneous alignment).

A portion of backlight from the backlight unit 4 passes through thefirst polarizer PL1 before entering the liquid crystal display panelLPN. The polarization state of the light that has entered the liquidcrystal display panel LPN depends on the alignment state of the liquidcrystal molecules LM when passing through the liquid crystal layer LQ.The light that has passed through the liquid crystal layer LQ duringoff-states is absorbed by the second polarizer PL2 (black display).

On the other hand, when a voltage is applied to the liquid crystal layerLQ, that is, an electric field is produced between the pixel electrodePE and the common electrode CE (during on-states), a transverse electricfield (or an oblique electric field) substantially parallel to thesubstrate is produced between the pixel electrode PE and the commonelectrode CE. Under the influence of the electric field, the major axisof the liquid crystal molecules LM rotates, as indicated by a solid linein FIG. 2, in a plane substantially parallel to the X-Y plane.

In the example shown in FIG. 2, the liquid crystal molecules LM in anarea between the pixel electrode PE and the primary common electrode CAon the left side rotate clockwise around the second direction Y and areoriented toward the lower left in FIG. 2. The liquid crystal moleculesLM in an area between the pixel electrode PE and the primary commonelectrode CA on the right side rotate counterclockwise around the seconddirection Y and are oriented toward the lower right in FIG. 2.

Thus, in a state in which an electric field is produced between thepixel electrode PE and the common electrode CE in each pixel PX, thealignment direction of the liquid crystal molecules LM is divided into aplurality of directions with the pixel electrode PE acting as a boundaryto form a domain in each alignment direction. That is, a plurality ofdomains is formed for each pixel PX.

A portion of backlight entering the liquid crystal display panel LPNfrom the backlight unit 4 during such on-states passes through the firstpolarizer PL1 followed by entering the liquid crystal display panel LPN.The backlight having entered the liquid crystal layer LQ changes in itspolarization state. During such on-states, at least a portion of lighthaving passed through the liquid crystal layer LQ passes through thesecond polarizer PL2 (white display).

FIG. 5 is a diagram illustrating an electric field produced between thepixel electrode PE and the common electrode CE in the liquid crystaldisplay panel LPN shown in FIGS. 2 and 4 and a relationship between adirector of the liquid crystal molecules LM and transmittance by theelectric field. Here, the description focuses on the pixel electrode PE(primary pixel electrode PA) and the common electrode CE (primary commonelectrode CA).

As shown in FIG. 5, the liquid crystal molecules LM are initiallyaligned substantially parallel to the second direction Y duringoff-states. During on-states in which a potential difference is producedbetween the pixel electrode PE and the common electrode CE, the opticalmodulation percentage of the liquid crystal is the highest (that is, thetransmittance is the highest in an opening) when the director (or themajor axis direction of the liquid crystal molecules LM) of the liquidcrystal molecules LM is shifted by about 45° with respect to the firstpolarization axis AX1 of the first polarizer PL1 and the secondpolarization axis AX2 of the second polarizer PL2 in the X-Y plane. Inthe illustrated example, when the pixel becomes on-state, the directorsof the liquid crystal molecules LM between the primary common electrodeCA on the left side and the pixel electrode PE are substantiallyparallel at azimuth angles 45°, −225° in the X-Y plane and the directorsof the liquid crystal molecules LM between the primary common electrodeCA on the right side and the pixel electrode PE are substantiallyparallel at azimuth angles 135°, −315° in the X-Y plane to achieve thepeak transmittance. If the transmittance distribution per pixel isfocused on, while the transmittance is substantially zero on the pixelelectrode PE and the common electrode CE, a high transmittance is gainedover substantially the entire area of the electrode gap between thepixel electrode PE and the common electrode CE.

The primary common electrode CA positioned just above the source wiringS is opposed to the black matrix BM and the primary common electrode CAhas a width less than or equal to that of the black matrix BM in thefirst direction X and does not extend to the side of the pixel electrodePE from the position overlapping the black matrix BM. Thus, an openingcontributing to the display per pixel corresponds to an area between thepixel electrode PE and a pair of the adjacent primary common electrodesCA of regions between the black matrixes BM or between a pair of theadjacent source wirings S.

FIG. 6 is a plan view schematically showing a corner of the display areaACT and the non-display area R of the array substrate AR. FIG. 7 is asectional view schematically showing a structure example of the arraysubstrate AR along line VII-VII in FIG. 6.

As shown in FIGS. 6 and 7, the array substrate AR includes a peripheralwiring 31 located in the non-display area R, another peripheral wiring32, and a peripheral connecting electrode 33. The peripheral wiring 31and the peripheral wiring 32 are provided on the first interlayerinsulating 11 of the same material together with the source wiring S orthe like. A metallic material such as Al can be used as the abovematerial. The peripheral wiring 32 is set to the same potential as theperipheral wiring 31.

The peripheral connecting electrode 33 is a solid electrode in arectangular frame shape located in the non-display area R in arectangular frame shape and is provided on the second interlayerinsulating 12 of the same material together with the pixel electrode PEand the shield electrode SE. Here, the peripheral connecting electrode33 is formed integrally with the shield electrode SE.

The peripheral connecting electrode 33 is connected to the peripheralwiring 31 through a contact hole CH4 formed in the second interlayerinsulating 12 and connected to the peripheral wiring 32 through acontact hole CH5 formed in the second interlayer insulating 12. Thus,the peripheral connecting electrode 33 electrically connects the shieldelectrode SE and the peripheral wiring 31 and also the shield electrodeSE and the peripheral wiring 32.

As shown in FIG. 1, the array substrate AR includes a feed unit VS toapply a voltage to the common electrode CE. The feed unit VS is formed,for example, in the non-display area R. A portion of the commonelectrode CE is pulled out to the non-display area R. Though notillustrated here, the liquid crystal display apparatus further includesa conductive member provided between the array substrate AR and thecountersubstrate CT. A portion of the common electrode CE (FIG. 3) iselectrically connected to the feed unit VS via the conductive member.

The array substrate AR further includes a voltage supply wiring locatedin the non-display area R, electrically connected to the commonelectrode CE (primary common electrode CA) via the conductive member,and capable of supplying a common voltage to the common electrode CE.

As shown in FIGS. 1, 6, and 7, the feed unit VS in the presentembodiment is formed of a portion of the peripheral wiring 31. Thus, theperipheral wiring 31 and the voltage supply wiring are shared. In such acase, the peripheral wiring 31 can be called a common wiring (Vcomwiring).

Incidentally, the feed unit VS may also be formed of a portion of theperipheral wiring 32. Thus, the peripheral wiring 32 and the voltagesupply wiring are shared. In such a case, the peripheral wiring 32 canbe called a common wiring (Vcom wiring).

FIG. 8 is a schematic view showing the entire peripheral wirings 31, 32located in the non-display area R of the array substrate AR.

As shown in FIG. 8, the peripheral wiring 31 is provided on the left andright sides of the display area ACT and the peripheral wiring 32 isprovided on the side above or below the display area ACT on which thereis no drive circuit. The peripheral wirings 31, 32 surround three sidesof the display area ACT. In other words, peripheral wirings in thepresent embodiment are formed in an angular U shape or a Π shapeexcluding one edge side on which pads of outer lead bonding (OLB) arearranged. By arranging peripheral wirings in a Π shape excluding oneside of four sides in this manner, portions where the peripheral wiringsintersect with wirings pulled out of the display area to the OLB padsare reduced so that yields are improved by preventing defects such asshort circuits.

The shield electrode SE is connected, as described above, to both endsof the peripheral wiring 31 and the peripheral wiring 32 through contactholes CH4 and CH5 via the peripheral connecting electrode 33, but if theshield electrode SE and the peripheral connecting electrode 33 areconnected by one side of the peripheral wirings 31, 32, the potential ofthe shield electrode SE becomes more unstable with an increasingdistance from the connected location, generating concern that asufficient shield effect may not be attained.

By connecting the shield electrode SE and the peripheral connectingelectrode 33 by three side of the left and right sides of the peripheralwiring 31 and the upper side of the peripheral wiring 32 like in thepresent embodiment, a stable potential can be supplied to the shieldelectrode SE over the entire region of the display area ACT so that asufficient shield effect can be attained. Further, with the peripheralconnecting electrode 33 being arranged in a rectangular frame shapesurrounding four sides of the display area ACT, a balanced potential canbe supplied without generating a potential difference inside the shieldelectrode SE.

Each of the peripheral wirings 31, 32 may be interconnected, but mayalso be arranged independently. When the peripheral wirings 31, 32 arearranged independently, each peripheral wiring need only have the samepotential applied thereto.

The peripheral connecting electrode 33 is arranged, as described above,like surrounding four sides of the display area ACT. The peripheralwirings are arranged in a lower layer of the peripheral connectingelectrode 33 via a insulating film and on three sides of the displayarea ACT. Further, the peripheral connecting electrode and peripheralwirings are electrically connected through contact holes. By surroundingthe display area ACT by the peripheral connecting electrode andperipheral wirings as described above, charges such as staticelectricity can be prevented from entering from outside to generateworkings to protect wirings and circuits in the liquid crystal displayapparatus.

According to a liquid crystal display apparatus configured as describedabove, the liquid crystal display apparatus includes the array substrateAR, the countersubstrate CT, and the liquid crystal layer LQ. The arraysubstrate AR includes the gate wiring G, the source wiring S, the secondinterlayer insulating 12, the shield electrode SE, the primary pixelelectrode PA, the peripheral wiring 31, and the peripheral connectingelectrode 33. The shield electrode SE is provided on the secondinterlayer insulating 12 and opposed to the gate wiring G and the sourcewiring S. The peripheral wiring 31 is located in the non-display area R.The peripheral connecting electrode 33 electrically connects the shieldelectrode SE and the peripheral wiring 31.

Thus, the potential of the shield electrode SE can be set and the samepotential as that of the primary common electrode CA can be applied tothe shield electrode SE. Moreover, the above setting can be realizedwithout increasing the manufacturing process or significantly changingthe layout. Thus, undesired electric fields from the source wiring S andthe gate wiring G can be shielded. Because the occurrence of lightleakage caused by undesired movement of liquid crystal molecules can bereduced, degradation in display quality can be restricted.

From the above, a liquid crystal display apparatus superior in displayquality can be obtained.

Further, according to the present embodiment, a high transmittance isgained in an electrode gap between the pixel electrode PE and the commonelectrode CE and therefore, the transmittance per pixel can be madesufficiently high by increasing the inter-electrode distance between thepixel electrode PE and the common electrode CA. Moreover, productspecifications of different pixel pitches can be handled by changing theinter-electrode distance (that is, by changing the arrangement positionof the primary common electrode CA with respect to the pixel electrodePE arranged in a substantial center of the pixel PX). That is, in adisplay mode according to the present embodiment, products of variouspixel pitches can be provided by setting the inter-electrode distancewithout necessarily needing fine electrode workings ranging from productspecifications of low resolution of a relatively large pixel pitch toproduct specifications of high resolution of a relatively small pixelpitch. Therefore, requirements of high transmittance and high resolutioncan easily be realized.

Further, according to the present embodiment, focusing on thetransmittance distribution in an area overlapping the black matrix BM,it is found that the transmittance is sufficiently decreased. This isbecause no leakage of electric field to the outside of the pixel fromthe position of the common electrode CE occurs and no undesiredtransverse electric field is generated between adjacent pixels acrossthe black matrix BM and thus, liquid crystal molecules in a regionoverlapping the black matrix BM maintain the initial alignment statelike during off-states (or during a black display condition). Therefore,even if adjacent pixels have color filters in different colors, theoccurrence of color mixing can be restricted so that lower colorreproducibility and a lower contrast ratio can be restricted.

When displacements of the array substrate AR and the countersubstrate CTare caused, a difference of horizontal inter-electrode distances in thecommon electrodes CE on both sides across the pixel electrode PE mayarise. However, such displacements arise for all the pixels PX in commonand therefore, there is no difference in the distribution of electricfield between the pixels PX and the influence thereof on the display ofimages is extremely small. Furthermore, even if displacements arisebetween the array substrate AR and the countersubstrate CT, undesiredleakage of electric field to adjacent pixels can be restricted.Therefore, even if adjacent pixels have color filters of differentcolors, the occurrence of color mixing can be restricted so that lowercolor reproducibility and a lower contrast ratio can be restricted.

Further, according to the present embodiment, the primary commonelectrode CA is opposed to each source wiring S. Particularly when theprimary common electrode CA is arranged just above the source wiring S,the opening AP is enlarged and so the transmittance of the pixel PX canbe improved.

Also by arranging the primary common electrode CA just above the sourcewiring S, the inter-electrode distance between the pixel electrode PEand the primary common electrode CA can be increased so that a morehorizontal transverse electric field can be produced. Therefore, a widerrange of viewing angle as an advantage of the IPS mode and the like,which is a conventional configuration, can also be maintained.

Further, according to the present embodiment, a plurality of domains canbe formed in a pixel. Therefore, the viewing angle can optically becompensated for in a plurality of directions so that the wider ofviewing angle can be achieved.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

The shield electrode SE need only be opposed to at least a portion ofthe gate wiring G and the source wiring S. For example, the shieldelectrode SE need only be opposed to only the gate wiring G or only thesource wiring S.

The peripheral connecting electrode 33 is connected to the peripheralwirings 31, 32 via contact holes CH4 and CH5 respectively, but theposition, size and number of connection portions are not limited to theabove example and various modifications thereof can be made. In thiscase, such modifications can be made by adjusting the arrangement, size,and shape of the peripheral connecting electrode 33 and the peripheralwirings 31, 32. For example, the peripheral connecting electrode 33 needonly be electrically connected to the shield electrode SE and need notbe a solid electrode.

The shield electrode SE need only be electrically connected to at leastthe peripheral wiring 31.

The peripheral connecting electrode 33 and the shield electrode SE maybe, in addition to a transparent electrode such as ITO, an opaqueconductive material such as aluminum, silver, and copper.

In the above example, a case when the initial alignment direction of theliquid crystal molecules LM is parallel to the second direction Y isdescribed, but may be, as shown in FIG. 2, an oblique direction Dobliquely crossing the second direction Y. An angle θ1 formed by theinitial alignment direction D with the second direction Y is greaterthan 0° and less than 45°. From the perspective of alignment control ofthe liquid crystal molecules LM, it is very effective to set 81 to about5 to 30°, more desirably 20° or less. That is, the initial alignmentdirection of the liquid crystal molecules LM is desirably substantiallywithin the range of 0 to 20° with respect to the second direction Y.

In the above example, a case when the liquid crystal layer LQ isconstituted of a liquid crystal material whose dielectric anisotropy ispositive (positive type) is described, but the liquid crystal layer LQmay also be constituted of a liquid crystal material whose dielectricanisotropy is negative (negative type). Though a detailed description isomitted, because the dielectric anisotropy is reversed between positiveand negative, if the liquid crystal material is positive type liquidcrystal material, it is preferable to set 81 to 45 to 90°, desirably 70°or more.

Because a transverse electric field is hardly produced (or a sufficientelectric field to drive the liquid crystal molecules LM is not produced)on the pixel electrode PE or the common electrode CE even duringon-states, the liquid crystal molecules LM hardly move from the initialalignment direction like during off-states. Thus, even if the pixelelectrode PE and the common electrode CE are formed of a conductivematerial having light transmission properties such as ITO, backlighthardly passes through such areas, making little contribution to thedisplay during on-states. Therefore, the pixel electrode PE and thecommon electrode CE do not have to be formed of a transparent conductivematerial and may be formed using a conductive material such as aluminum,silver, and copper.

In the present embodiment, the structure of the pixel PX is not limitedto the examples shown in FIGS. 2 and 4 and various modifications may bemade. The pixel PX need only include, at least, one or more primarypixel electrode (PA) extending along the major axis of the pixel PXformed on the array substrate AR and a plurality of primary commonelectrodes (CA) extending in the major axis direction of the pixel PXformed on the countersubstrate CT and positioned across the primarypixel electrode in the minor axis direction of the pixel PX.

The shape of the pixel electrode PE can be changed in various ways andmay have a cross shape, T shape, or I shape. For example, the pixelelectrode PE can be formed in a cross shape by changing the shape of thesecondary pixel electrode PB. In addition, the pixel electrode PE mayhave a V shape. In this case, the primary pixel electrode PA is notformed by linearly extending in the second direction Y, but is formed bybending in the center portion thereof.

The common electrode CE may contain, in addition to the primary commonelectrodes CA, a secondary common electrode formed on thecounterelectrode CT and extending in the first direction X. Thesecondary common electrode is set to have the same potential as theprimary common electrode CA. Because the shield electrode SE is also setto have the same potential as the primary common electrode CA, theshield electrode SE may also be called a secondary common electrode.

The primary common electrode CA and the secondary common electrodeformed on the countersubstrate CT are formed integrally andsuccessively. The secondary common electrode formed on thecountersubstrate CT is opposed to each of the gate wirings G.

1. A liquid crystal display apparatus, comprising: a first substratethat includes a gate wiring located in a display area and configured toextend in a first direction, a source wiring located in the display areaand configured to extend in a second direction orthogonal to the firstdirection, an insulating film provided on the gate wiring and the sourcewiring, a shield electrode provided on the insulating film and oppositeto at least a portion of the gate wiring and the source wiring, aprimary pixel electrode located in the display area, provided on theinsulating film, positioned with an interval from the shield electrode,and configured to extend in the second direction, a peripheral wiringlocated in a non-display area outside the display area, and a peripheralconnecting electrode electrically connecting the shield electrode andthe peripheral wiring; a second substrate that includes a pair ofprimary common electrodes located in the display area, positioned acrossthe primary pixel electrode in the first direction, and configured toextend in the second direction; and a liquid crystal layer held betweenthe first substrate and the second substrate.
 2. The liquid crystaldisplay apparatus according to claim 1, further comprising: a conductivemember provided between the first substrate and the second substrate,wherein the first substrate further includes a voltage supply wiringlocated in the non-display area, connected electrically to the pair ofprimary common electrodes via the conductive member, and configured tosupply a common voltage to the pair of primary common electrodes, andthe peripheral wiring and the voltage supply wiring are configured toshare.
 3. The liquid crystal display apparatus according to claim 1,further comprising: a conductive member provided between the firstsubstrate and the second substrate, wherein the first substrate furtherincludes a voltage supply wiring located in the non-display area,connected electrically to the pair of primary common electrodes via theconductive member, and configured to supply a common voltage to the pairof primary common electrodes, and another peripheral wiring located inthe non-display area and configured to set to a potential equal to thepotential of the peripheral wiring, and the other peripheral wiring andthe voltage supply wiring are configured to share.
 4. The liquid crystaldisplay apparatus according to claim 1, wherein the primary pixelelectrode, the shield electrode, and the peripheral connecting electrodeare formed of the same material.
 5. The liquid crystal display apparatusaccording to claim 1, wherein the peripheral connecting electrode islocated in the non-display area and surrounded the display area, and theperipheral wiring is located in the non-display area and surroundedthree sides of the display area.
 6. The liquid crystal display apparatusaccording to claim 5, wherein the peripheral connecting electrode is asolid electrode in a rectangular frame shape.
 7. The liquid crystaldisplay apparatus according to claim 1, wherein the peripheral wiring isformed of the same material as the source wiring.
 8. The liquid crystaldisplay apparatus according to claim 1, wherein the peripheral wiring isprovided in the same layer as the source wiring.
 9. The liquid crystaldisplay apparatus according to claim 1, wherein the shield electrodeopposite to the gate wiring has a width greater than or equal to a widthof the gate wiring.
 10. The liquid crystal display apparatus accordingto claim 1, wherein the shield electrode opposite to the source wiringhas a width greater than or equal to a width of the source wiring.
 11. Aliquid crystal display apparatus, comprising: a first substrate thatincludes a gate wiring configured to extend in a first direction, asource wiring configured to extend in a second direction orthogonal tothe first direction, an insulating film provided on the gate wiring andthe source wiring, a shield electrode provided on the insulating filmand opposite to at least a portion of the gate wiring and the sourcewiring, a primary pixel electrode provided on the insulating film,positioned with an interval from the shield electrode, and configured toextend in the second direction, a peripheral wiring provided in the samelayer as the source wiring, and a peripheral connecting electrodeelectrically connecting the shield electrode and the peripheral wiring;a second substrate that includes a pair of primary common electrodespositioned across the primary pixel electrode in the first direction andconfigured to extend in the second direction; and a liquid crystal layerheld between the first substrate and the second substrate.
 12. Theliquid crystal display apparatus according to claim 11, wherein theperipheral wiring is arranged in a Π shape.
 13. The liquid crystaldisplay apparatus according to claim 12, wherein the primary pixelelectrode, the shield electrode, and the peripheral connecting electrodeare formed of the same material.
 14. The liquid crystal displayapparatus according to claim 12, wherein the peripheral connectingelectrode is a solid electrode in a rectangular frame shape.
 15. Aliquid crystal display apparatus, comprising: a first substrate thatincludes a gate wiring located in a display area and configured toextend in a first direction, a first interlayer film provided on thegate wiring, a source wiring configured to extend in a second directionorthogonal to the first direction on the first interlayer film in thedisplay area, a second interlayer film provided on the source wiring, aprimary pixel electrode configured to extend in the second direction onthe second interlayer film in the display area, a secondary pixelelectrode connected to the primary pixel electrode and configured toextend in the first direction; and a peripheral wiring provided in a Πshape on the first interlayer film in a non-display area outside thedisplay area; a second substrate that includes a primary commonelectrode located in the display area, arranged parallel to the primarypixel electrode, and configured to extend in the second direction; and aliquid crystal layer held between the first substrate and the secondsubstrate and including a cell gap narrower than an interval between theprimary pixel electrode and the primary common electrode.
 16. The liquidcrystal display apparatus according to claim 15, wherein a wiring pulledout of the display area is configured to pass through the non-displayarea deviating from the peripheral wiring.
 17. The liquid crystaldisplay apparatus according to claim 16, wherein the peripheral wiringis formed of the same material as the source wiring.
 18. The liquidcrystal display apparatus according to claim 15, further comprising: aconductive member provided between the first substrate and the secondsubstrate, wherein the first substrate further includes a voltage supplywiring located in the non-display area, connected electrically to theprimary common electrode via the conductive member, and configured tosupply a common voltage to the primary common electrode and theperipheral wiring and the voltage supply wiring are configured to share.19. The liquid crystal display apparatus according to claim 18, whereinthe first substrate further includes a peripheral connecting electrodein the same layer as the primary pixel electrode in the non-displayarea, the peripheral connecting electrode is a solid electrode in arectangular frame shape, and a portion of the peripheral connectingelectrode is connected to the peripheral wiring.
 20. The liquid crystaldisplay apparatus according to claim 19, wherein the first substratefurther includes a shield electrode provided on the second interlayerfilm and the shield electrode is opposite to at least one of the gatewiring and the source wiring and connected to the peripheral connectingelectrode.